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Selecting X TOP records
Message
De
11/10/2004 12:58:56
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00950435
Message ID:
00950474
Vues:
16
>Am I correct in assuming that when you use SQL Select, the TOP syntax is not optimized for an index?
>
>I have a table MYORDERS with field ORDERNO that has index tag.
>
>When I try:
>
>
>select top 10 * from MYORDERS order by ORDERNO
>
>
>The query takes considerable time. I can sort of "see" that VFP selects all records and then selects 10 from the top. Is there a way to make this query run faster?
>

Use VFP 9. This is one of the areas where performance has improved in VFP 9. When I last tested, I couldn't see a difference between 8 and 9 on a medium-size table (about 75,000 records), but selecting the top 20 out of a million took about 1/3 the time in VFP 9 as in VFP 8.

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